When three solid-state relays are connected in series, the supply voltage must be?

Connecting three solid-state relays in series requires careful consideration of how the total voltage is distributed among them. Each relay has a minimum operating voltage necessary to function effectively, and that minimum is typically defined by the specifications of the relay itself.

When three relays are connected in series, the supply voltage must not only meet the minimum operating voltage of one relay but must also accommodate each additional relay in the chain. Since each relay will have its own minimum operating voltage, the total required supply voltage becomes three times that of a single relay's minimum operating voltage.

This ensures that each relay receives sufficient voltage to operate correctly, preventing any of them from potentially failing to switch due to inadequate voltage. The need for this configuration arises from the characteristics of solid-state relays—where maintaining the operational integrity of each unit in such a setup is paramount for reliable performance.